/**
 * Given a string S and a string T, count the number of distinct subsequences of T in S.
 * A subsequence of a string is a new string which is formed from the original string by 
 * deleting some (can be none) of the characters without disturbing the relative positions 
 * of the remaining characters. (ie, "ACE" is a subsequence of "ABCDE" while "AEC" is not).
 * Here is an example:S = "rabbbit", T = "rabbit"
 * Return 3.
 */
/**
 * @author Ivan
 *
 */
package problem115_Distinct_Subsequences;